Household Income, Cortisol, and Obesity During Early Childhood: A Prospective Longitudinal Study.

OBJECTIVE: To prospectively evaluate the relationship between household income, children's cortisol, and body mass index (BMI) trajectories over a 3-year period in early childhood. STUDY DESIGN: Household income, child hair cortisol levels, and BMI were measured at baseline, 12-, 24-, and 36-month follow-up visits in the Now Everybody Together for Amazing and Healthful Kids (NET-Works) Study (n = 534, children ages 2-4 years, and household income <$65 000/year at baseline). Relationships were examined between very low household income (<$25 000/year) at baseline, income status over time (remained <$25 000/year or had increasing income), cortisol accumulation from hair samples, and BMI percent of the 95th percentile (BMIp95) trajectories using adjusted linear growth curve modeling. Households with baseline income between $25 000 and $65 000/year were the reference group for all analyses. RESULTS: Children from very low-income households at baseline had annual changes in BMIp95 that were higher (P < .001) than children from reference group households (0.40 vs -0.62 percentage units/year). Annual increases in BMIp95 were also greater among children from households that remained very low income (P < .01, .34 percentage units/year) and among those with increasing income (P = .01, .51 percentage units/year) compared with the reference group (-0.61 percentage units/year). Children from households that remained very low income had higher hair cortisol accumulations (0.22 pg/mg, P = .02) than reference group children, whereas hair cortisol concentrations of children from households with increasing income (0.03 pg/mg) did not differ significantly from the reference group. Cortisol was not related to BMIp95. CONCLUSIONS: The economic circumstances of families may impact children's BMI trajectories and their developing stress systems, but these processes may be independent of one another.

Is economic hardship associated with young children's cortisol levels?

Economic hardship during childhood has been linked to poor physical and mental health. This study examines cross-sectional and longitudinal associations of a summed economic hardship score of poverty, food insecurity, and financial hardship with hair cortisol in young children. Data from 24-month (Time 1, mean age 5 years) and 36-month (Time 2, mean age 6 years) follow-up from the NET-Works obesity prevention trial (NET-Works, NCT0166891) were used. Hair cortisol measures obtained at each time point were log-transformed and regressed on economic hardship at Time 1 and a cumulative economic hardship from Time 1 to Time 2, using generalized linear regressions. All models were adjusted for child age, sex, race/ethnicity, and intervention (prevention vs. control) arm. The final analytic sample sizes ranged from 248 to 287. Longitudinal analyses indicated that for every 1-unit higher economic hardship score at Time 1, hair cortisol at Time 2 follow-up was on average 0.07 log-picograms per milligram (pg/mg) higher (95% confidence interval [CI]: 0.01, 0.13). For every 1-unit increase in the cumulative economic hardship score between Time 1 and 2, there was a 0.04 log-pg/mg (95% CI: 0.00, 0.07) average higher level of hair cortisol at Time 2 follow-up. Results show suggestive but limited evidence for an association between economic hardship and cortisol in young children.

The relative contributions of adiposity and activity levels to physical performance in children with excess weight.

OBJECTIVE: This study examined predictors of physical performance, a key aspect of quality of life, in children with excess weight. METHODS: Participants were 269 children aged 6-12 years with a body mass index above the 85th percentile. Children completed a standardized physical performance task capturing lower extremity strength, balance, and gait speed. Height, weight, and waist circumference were objectively measured, and daily moderate-vigorous physical activity (min/day) and sedentary time (% of day) were assessed with a 7-day accelerometer protocol. RESULTS: Physical performance task completion averaged 15.0 (SD = 2.5) seconds. Children with higher body mass index z-scores and waist circumferences had significantly longer task completion times. The task took 1.8 additional seconds per 1.0 body mass index z-score (p < .001), and 1.2 additional seconds for every 20 cm higher waist circumference (p < .001). Daily moderate-vigorous physical activity and sedentary time were unrelated to physical performance, and did not moderate its associations with the adiposity measures. CONCLUSION: Among children with excess weight, physical performance declines with increasing levels of total and central adiposity. Daily activity levels do not moderate this association. Interventions that directly target weight reduction would likely yield the greatest improvement in physical performance in children with overweight or obesity.

The impact of financial incentives and restrictions on cyclical food expenditures among low-income households receiving nutrition assistance: a randomized controlled trial.

BACKGROUND: The Supplemental Nutrition Assistance Program (SNAP) is the largest anti-hunger program in the United States. Two proposed interventions to encourage healthier food expenditures among SNAP participants have generated significant debate: financial incentives for fruits and vegetables, and restrictions on foods high in added sugar. To date, however, no study has assessed the impact of these interventions on the benefit cycle, a pattern of rapid depletion of SNAP benefits that has been linked to worsening nutrition and health outcomes over the benefit month. METHODS: Low-income households not currently enrolled in SNAP (n = 249) received benefits every 4 weeks for 12 weeks on a study-specific benefit card. Households were randomized to one of four study arms: 1) incentive (30% incentive for fruits and vegetables purchased with study benefits), 2) restriction (not allowed to buy sugar-sweetened beverages, sweet baked goods, or candy using study benefits), 3) incentive plus restriction, or 4) control (no incentive or restriction). Weekly household food expenditures were evaluated using generalized estimating equations. RESULTS: Compared to the control group, financial incentives increased fruit and vegetable purchases, but only in the first 2 weeks after benefit disbursement. Restrictions decreased expenditures on foods high in added sugar throughout the benefit month, but the magnitude of the impact decreased as the month progressed. Notably, restrictions mitigated cyclical expenditures. CONCLUSIONS: Policies to improve nutrition outcomes among SNAP participants should consider including targeted interventions in the second half of the month to address the benefit cycle and attendant nutrition outcomes. TRIAL REGISTRATION: ClinicalTrial.gov, NCT02643576 . Retrospectively registered December 22, 2014.

Designing online grocery stores to support healthy eating for weight loss.

OBJECTIVES: The current study aimed to identify features to include in online grocery stores to support healthful food purchasing by those striving to lose weight. DESIGN: A Value Proposition Design approach was used to gain shopper insights, devise potential online grocery store features and obtain feedback on these features. SETTING: Telephone interviews were conducted to gain insight into shoppers' needs and perceptions. Results were used by the research team to identify potential online grocery shopping features that may support healthful purchase decisions, and interviews were conducted with a different sample of shoppers to gather feedback on features. PARTICIPANTS: Insight (n 25) and feedback (n 25) interviews were conducted with convenience samples of adults trying to lose weight. RESULTS: Participants were primarily female, white, college educated and with obesity or overweight. Online grocery features devised by the research team based on findings from the insight interviews included (1) shopping cart nutrition rating tool; (2) healthy meal planning tool; (3) interactive healthy eating inspiration aisle and (4) healthy shopping preference settings option. Findings from the feedback interviews indicated that the healthy meal planning tool, healthy shopping preference settings option and shopping cart nutrition rating tool features were positively rated by most participants. CONCLUSIONS: There are multiple features grocers should consider including in their online stores to attract and support customers striving to eat healthy for weight loss.

Trends in cyclical food expenditures among low-income households receiving monthly nutrition assistance: results from a prospective study.

OBJECTIVE: Supplemental Nutrition Assistance Program (SNAP) benefits are rapidly depleted after distribution. This phenomenon, known as the benefit cycle, is associated with poor nutrition and health outcomes. However, to date, no study has evaluated trends in food expenditures before and after households receive benefits using prospective data, and whether these trends vary by household characteristics. DESIGN: Generalised estimating equations were used to model weekly household food expenditures during baseline (pre-benefit) and intervention months by vendor (restaurants and food retailers). Food retailer expenditures were further evaluated by food category (fruits and vegetables and foods high in added sugar). All expenditures were evaluated by household composition, demographics and economic means. SETTING: Minneapolis-St. Paul, Minnesota, metropolitan area. PARTICIPANTS: Low-income households (n 249) enrolled May 2013-August 2015. RESULTS: Weekly food retailer expenditures did not vary during baseline (pre-benefit), but demonstrated a cyclical pattern after households received benefits across all household characteristics and for both food categories, particularly for fruits and vegetables. Households with greater economic resources spent more throughout the month compared with those with fewer resources. Households with lower food security status experienced more severe fluctuations in spending compared with more food secure households. CONCLUSIONS: Cyclical food purchasing was observed broadly across different household characteristics and food categories, with notable differences by household economic means and food security status. Proposed SNAP policy changes designed to smooth food expenditures across the benefit month, such as increased frequency of benefit distribution, should include a focus on households with fewest resources.

Associations between shopper impulsivity and cyclical food purchasing: Results from a prospective trial of low-income households receiving monthly benefits.

Supplemental Nutrition Assistance Program (SNAP) benefits are rapidly depleted after distribution. This phenomenon, known as the benefit cycle, is associated with poor nutrition and health outcomes. Proposed interventions targeting the benefit cycle often focus on impulsive decision-making. However, it remains unclear whether shopper impulsivity is associated with food purchasing behavior. Using data from a prospective trial, we evaluate whether shopper impulsivity is associated with food purchasing behavior before and after households receive nutrition assistance. In this study, 249 low-income households in the Minneapolis-St. Paul, Minnesota, metropolitan area received monthly benefits for three months. Overall impulsivity and impulsivity subtraits of the primary shopper was assessed using the Barratt Impulsiveness Scale-11. Both total food expenditures and expenditures for two specific categories (fruits and vegetables, and foods high in added sugar) were evaluated. Generalized estimating equations were used to model household expenditures as a function of week since benefit distribution, impulsivity, and their interaction. Results showed that during the benefit period, food expenditures were cyclical and patterned by impulsivity. Shoppers with greater overall impulsivity spent $40.62 more in week 1 (p < 0.001). While more impulsive shoppers spent more on foods high in added sugar throughout the month (p < 0.05 for all weeks), no patterns were observed for fruits and vegetables. These findings suggest that greater impulsivity exacerbates cyclical food purchasing behavior. The impact of shopper impulsivity is especially notable for expenditures on foods high in added sugar. SNAP educational interventions to mitigate the benefit cycle may be strengthened by focusing on more impulsive shoppers and on strategies to reduce impulsive purchases of foods high in added sugar.

Assessment of Interrater Reliability of the Emergency Severity Index After Implementation in Emergency Departments in Jamaica Using a Learning Collaborative Approach.

INTRODUCTION: In 2016, the Ministry of Health in Jamaica selected the Emergency Severity Index as the triage tool to be used nationally. This study evaluated the effectiveness of this approach by assessing the interrater reliability among new users trained with minimal resources by 2 experienced trainers, 1 local and 1 international. METHODS: A retrospective case series review was conducted within an online learning collaborative framework. After completion of the training, the participants from each of the 19 clinical sites were asked to submit 2 triage cases per month for blinded review by the expert trainers. The triage categories assigned by each reviewer were compared with those assigned by the newly trained Emergency Severity Index providers. A weighted kappa value was calculated to assess the degree of agreement between the sites and the expert trainers. RESULTS: A total of 166 cases were received over the study period. Participation in the learning collaborative was consistently below 50%. The interrater reliability between the expert trainers (κ = 0.48) as well as between each scorer and each accident and emergency department site (κSF = 0.33, κPT = 0.26) was low, although there was improvement over the study period. Incomplete triage documentation limited raters' ability to assign triage categories and assess interrater reliability. DISCUSSION: Despite a rigorous implementation process, the interrater reliability of the Emergency Severity Index skills of Jamaican emergency nurses and doctors when compared with that of the 2 experts was poor. Several areas were identified for strengthening. Considerations for the implementation of the Emergency Severity Index in countries outside of the US were also discussed.

Weight change over 9 years and subsequent risk of venous thromboembolism in the ARIC cohort.

BACKGROUND/OBJECTIVES: Weight gain increases risk of cardiovascular disease, but has not been examined extensively in relationship to venous thromboembolism (VTE). The association between weight change over 9 years and subsequent VTE among participants in the Atherosclerosis Risk in Communities (ARIC) study was examined, with a hypothesis that excess weight gain is a risk factor for VTE, relative to no weight change. SUBJECTS/METHODS: Quintiles of 9-year weight change were calculated (visit 4 1996-1998 weight minus visit 1 1987-1989 weight in kg: Quintile 1: ≥-1.81 kg; Quintile 2: <-1.81 to ≤1.36 kg; Quintile 3: >1.36 to ≤4.08 kg; Quintile 4: >4.08 to ≤7.71 kg; Quintile 5: >7.71 kg). Incident VTEs from visit 4 (1996-1998) through 2015 were identified and adjudicated using medical records. Hazard ratios (HRs) were calculated using Cox models. RESULTS: 529 incident VTEs were identified during an average of 19 years of follow up. Compared to Quintile 2, participants in Quintile 5 of weight change had 1.46 times the rate of incident VTE (HR = 1.46 (95% CI 1.09, 1.95), adjusted for age, race, sex, income, physical activity, smoking, and prevalent CVD). The HR for Quintile 5 was modestly attenuated to 1.38 (95% CI 1.03, 1.84) when visit 1 BMI was included in the model. When examined separately, results were significant for unprovoked VTE, but not for provoked VTE. Among those obese at visit 1, both weight gain (HR 1.86 95% CI 1.27, 2.71) and weight loss (HR 2.11 95% CI 1.39, 3.19) were associated with incident VTE, compared with normal-weight participants with no weight change. CONCLUSIONS: Weight gain later life was associated with increased risk for unprovoked VTE. Among those with obesity, both weight gain and weight loss were associated with increased risk for VTE.

A Bidirectional Analysis of Feeding Practices and Eating Behaviors in Parent/Child Dyads from Low-Income and Minority Households.

OBJECTIVE: To prospectively examine the bidirectional relationship between parental feeding practices (eg, instrumental feeding, encouragement to eat) and child eating behaviors (eg, food responsiveness, emotional eating) in low-income, ethnically diverse preschool children over a 3-year period. STUDY DESIGN: Parent/child (age 2-4 years at baseline) pairs (n = 222 non-Hispanics; n = 312 Hispanics) participated in NET-Works (Now Everybody Together for Amazing and Healthful Kids), a randomized controlled trial carried out in community and in-home settings in urban areas of Minnesota. Data were collected at baseline and 12, 24, and 36 months. The present study is a secondary data analysis using cross-lagged models to identify bidirectional associations between parental feeding practices and child eating behaviors. RESULTS: Three models showed significant cross-lagged effects (P < .05): model 1, parental instrumental feeding influencing later child food responsiveness; model 2, parental emotional feeding influencing later child food responsiveness; and model 3, parental emotional feeding influencing later child eating satiety. Model 1 showed significant bidirectional temporal paths, whereas models 2 and 3 showed significant unidirectional temporal paths from parental feeding practices to child eating behaviors. CONCLUSIONS: Parental instrumental and emotional feeding practices prospectively influence child food responsiveness and satiety. This study demonstrates causal temporality between parental feeding practices and child eating behaviors. Heath care providers may want to use findings regarding parent feeding practices as part of their anticipatory guidance during well-child visits with parents of preschoolers.

Harnessing inter-disciplinary collaboration to improve emergency care in low- and middle-income countries (LMICs): results of research prioritisation setting exercise.

BACKGROUND: More than half of deaths in low- and middle-income countries (LMICs) result from conditions that could be treated with emergency care - an integral component of universal health coverage (UHC) - through timely access to lifesaving interventions. METHODS: The World Health Organization (WHO) aims to extend UHC to a further 1 billion people by 2023, yet evidence supporting improved emergency care coverage is lacking. In this article, we explore four phases of a research prioritisation setting (RPS) exercise conducted by researchers and stakeholders from South Africa, Egypt, Nepal, Jamaica, Tanzania, Trinidad and Tobago, Tunisia, Colombia, Ethiopia, Iran, Jordan, Malaysia, South Korea and Phillipines, USA and UK as a key step in gathering evidence required by policy makers and practitioners for the strengthening of emergency care systems in limited-resource settings. RESULTS: The RPS proposed seven priority research questions addressing: identification of context-relevant emergency care indicators, barriers to effective emergency care; accuracy and impact of triage tools; potential quality improvement via registries; characteristics of people seeking emergency care; best practices for staff training and retention; and cost effectiveness of critical care - all within LMICs. CONCLUSIONS: Convened by WHO and facilitated by the University of Sheffield, the Global Emergency Care Research Network project (GEM-CARN) brought together a coalition of 16 countries to identify research priorities for strengthening emergency care in LMICs. Our article further assesses the quality of the RPS exercise and reviews the current evidence supporting the identified priorities.

Importance of the Supplemental Nutrition Assistance Program in Rural America.

There is great interest in reshaping the Supplemental Nutrition Assistance Program (SNAP) so that it better supports family nutrition, and an array of program changes have been proposed.We note the importance of considering the unique needs of rural SNAP participants when considering and implementing these changes. We also describe the SNAP-related needs and challenges unique to rural SNAP participants, and through this lens we discuss changes to SNAP that have been proposed and special considerations related to each. The special considerations we identified include allowing canned, frozen, and dried fruits and vegetables as eligible items in financial incentive programs in rural areas; changing direct education programming to address transportation-related barriers many rural families face in attending in-person classes; and supporting rigorous research to evaluate the potential benefits and unintended consequences of proposed program changes for which scant high-quality evaluation data exist.Evaluation studies should include rural SNAP participants so that effects in this important population group are known.

Nutrition quality of food purchases varies by household income: the SHoPPER study.

BACKGROUND: Lower household income has been consistently associated with poorer diet quality. Household food purchases may be an important intervention target to improve diet quality among low income populations. Associations between household income and the diet quality of household food purchases were examined. METHODS: Food purchase receipt data were collected for 14 days from 202 urban households participating in a study about food shopping. Purchase data were analyzed using NDS-R software and scored using the Healthy Eating Index 2010 (HEI 2010). HEI total and subscores, and proportion of grocery dollars spent on food categories (e.g. fruits, vegetables, sugar sweetened beverages) were examined by household income-to-poverty ratio. RESULTS: Compared to lower income households, after adjusting for education, marital status and race, higher income households had significantly higher HEI total scores (mean [sd] = 68.2 [13.3] versus 51.6 [13.9], respectively, adjusted p = 0.05), higher total vegetable scores (mean [sd] = 3.6 [1.4] versus 2.3 [1.6], respectively, adjusted p < .01), higher dairy scores (mean [sd] = 5.6 [3.0] versus 5.0 [3.3], p = .05) and lower proportion of grocery dollars spent on frozen desserts (1% [.02] versus 3% [.07], respectively, p = .02). CONCLUSIONS: Lower income households purchase less healthful foods compared with higher income households. Food purchasing patterns may mediate income differences in dietary intake quality. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02073643.

Multicomponent Obesity Prevention Intervention in Low-Income Preschoolers: Primary and Subgroup Analyses of the NET-Works Randomized Clinical Trial, 2012-2017.

OBJECTIVES: To evaluate a multicomponent obesity prevention intervention among diverse, low-income preschoolers. METHODS: Parent-child dyads (n = 534) were randomized to the Now Everybody Together for Amazing and Healthful Kids (NET-Works) intervention or usual care in Minneapolis, MN (2012-2017). The intervention consisted of home visits, parenting classes, and telephone check-ins. The primary outcomes were adjusted 24- and 36-month body mass index (BMI). RESULTS: Compared with usual care, the NET-Works intervention showed no significant difference in BMI change at 24 (-0.12 kg/m2; 95% confidence interval [CI] = -0.44, 0.19) or 36 months (-0.19 kg/m2; 95% CI = -0.64, 0.26). Energy intake was significantly lower in the NET-Works group at 24 (-90 kcal/day; 95% CI = -164, -16) and 36 months (-101 kcal/day; 95% CI = -164, -37). Television viewing was significantly lower in the NET-Works group at 24 (rate ratio = 0.84; 95% CI = 0.75, 0.93) and 36 months (rate ratio = 0.88; 95% CI = 0.78, 0.99). Children with baseline overweight or obesity had lower BMI in the NET-Works group than those in usual care at 36 months (-0.71 kg/m2; 95% CI = -1.30, -0.12). Hispanic children had lower BMI in the NET-Works group than those in usual care at 36 months (-0.59 kg/m2; 95% CI = -1.14, -0.04). CONCLUSIONS: In secondary analyses, NET-Works significantly reduced BMI over 3 years among Hispanic children and children with baseline overweight or obesity. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01606891.

The effect of proportional v. value pricing on fountain drink purchases: results from a field experiment.

OBJECTIVE: Reducing sugar-sweetened beverage consumption is a public health priority, yet finding an effective and acceptable policy intervention is challenging. One strategy is to use proportional pricing (a consistent price per fluid ounce) instead of the typical value-priced approach where large beverages offer better value. The purpose of the present study was to evaluate whether proportional pricing affects the purchasing of fountain beverages at a university cinema concession stand. DESIGN: Four price strategies for beverages were evaluated over ten weekends of film screenings. We manipulated two factors: the price structure (value pricing v. proportional pricing) and the provision of information about the price per fluid ounce (labels v. no labels). The key outcomes were the number and size of beverages purchased. We analysed data using regression analyses, with standard errors clustered by film and controlling for the day and time of purchase. SETTING: A university cinema concession stand in Minnesota, USA, in spring 2015. SUBJECTS: University students. RESULTS: Over the study period (360 beverages purchased) there were no significant effects of the proportional pricing treatment. Pairing a label with the standard value pricing increased the likelihood of purchasing large drinks but the label did not affect purchasing when paired with proportional pricing. CONCLUSIONS: Proportional prices did not significantly affect the size of beverages purchased by students at a university cinema, but adding a price-per-ounce label increased large drink purchases when drinks were value-priced. More work is needed to address whether pricing and labelling strategies might promote healthier beverage purchases.

Preliminary evaluation of the Healthy Savings Program: a novel health insurance-based wellness programme to encourage healthy food purchases.

OBJECTIVE: To examine level of participation and satisfaction with the Healthy Savings Program (HSP), a programme that provides price discounts on healthier foods. DESIGN: For Study 1, a survey was distributed to a random sample of adults who were invited to participate in a version of the HSP that provided a discount for the purchase of fresh produce and discounts on other healthier foods. In Study 2, interviews were conducted with a convenience sample of adults invited to participate in a version of the HSP that provided price discounts on specific products only (no fresh produce discount). SETTING: The HSP is provided to all employer-based insurance plan members of a large health plan. Employers can choose to enhance the version of the HSP that their employees receive by paying for a weekly discount on fresh produce. SUBJECTS: Employees in employer groups that received the enhanced HSP (Study 1) and employees in an employer group (Study 2) that received the standard HSP. RESULTS: Among survey respondents in Study 1, 69·3 % reported using the HSP card. Most were satisfied with the fresh produce discount and ease of use of the HSP card. Satisfaction was lower for selection of participating stores, amounts of discounts and selection of discounted products. In Study 2, barriers to the use of the HSP card cited included the limited number of participating stores and the limited selection of discounted products. CONCLUSIONS: Satisfaction with some elements of the HSP was high while other elements may need improvement to increase programme use.

Leveraging delay discounting for health: Can time delays influence food choice?

Delay discounting, the tendency to choose smaller immediate rewards over larger delayed rewards, is theorized to promote consumption of immediately rewarding but unhealthy foods at the expense of long-term weight maintenance and nutritional health. An untested implication of delay discounting models of decision-making is that selectively delaying access to less healthy foods may promote selection of healthier (immediately available) alternatives, even if they may be less desirable. The current study tested this hypothesis by measuring healthy versus regular vending machine snack purchasing before and during the implementation of a 25-s time delay on the delivery of regular snacks. Purchasing was also examined under a $0.25 discount on healthy snacks, a $0.25 tax on regular snacks, and the combination of both pricing interventions with the 25-s time delay. Across 32,019 vending sales from three separate vending locations, the 25-s time delay increased healthy snack purchasing from 40.1% to 42.5%, which was comparable to the impact of a $0.25 discount (43.0%). Combining the delay and the discount had a roughly additive effect (46.0%). However, the strongest effects were seen under the $0.25 tax on regular snacks (53.7%) and the combination of the delay and the tax (50.2%). Intervention effects varied substantially between vending locations. Importantly, time delays did not harm overall vending sales or revenue, which is relevant to the real-world feasibility of this intervention. More investigation is needed to better understand how the impact of time delays on food choice varies across populations, evaluate the effects of time delays on beverage vending choices, and extend this approach to food choices in contexts other than vending machines. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02359916.

To what extent do food purchases reflect shoppers' diet quality and nutrient intake?

BACKGROUND: Food purchasing is considered a key mediator between the food environment and eating behavior, and food purchasing patterns are increasingly measured in epidemiologic and intervention studies. However, the extent to which food purchases actually reflect individuals' dietary intake has not been rigorously tested. This study examined cross-sectional agreement between estimates of diet quality and nutrient densities derived from objectively documented household food purchases and those derived from interviewer-administered 24-h diet recalls. A secondary aim was to identify moderator variables associated with attenuated agreement between purchases and dietary intake. METHODS: Primary household food shoppers (N = 196) collected and annotated receipts for all household food and beverage purchases (16,356 total) over 14 days. Research staff visited participants' homes four times to photograph the packaging and nutrition labels of each purchased item. Three or four multiple-pass 24-h diet recalls were performed within the same 14-d period. Nutrient densities and Healthy Eating Index-2010 (HEI-2010) scores were calculated from both food purchase and diet recall data. RESULTS: HEI-2010 scores derived from food purchases (median = 60.9, interquartile range 49.1-71.7) showed moderate agreement (ρc = .57, p < .0001) and minimal bias (-2.0) with HEI-2010 scores from 24-h recalls (median = 60.1, interquartile range 50.8-73.9). The degree of observed bias was unrelated to the number of food/beverage purchases reported or participant characteristics such as social desirability, household income, household size, and body mass. Concordance for individual nutrient densities from food purchases and 24-h diet recalls varied widely from ρc = .10 to .61, with the strongest associations observed for fiber (ρc = .61), whole fruit (ρc = .48), and vegetables (ρc = .39). CONCLUSIONS: Objectively documented household food purchases yield an unbiased and reasonably accurate estimate of overall diet quality as measured through 24-h diet recalls, but are generally less useful for characterizing dietary intake of specific nutrients. Thus, some degree of caution is warranted when interpreting food purchase data as a reflection of diet in epidemiological and clinical research. Future work should examine agreement between food purchases and nutritional biomarkers. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02073643 . Retrospectively registered.

Financial incentives and purchase restrictions in a food benefit program affect the types of foods and beverages purchased: results from a randomized trial.

BACKGROUND: This research evaluated the effects of financial incentives and purchase restrictions on food purchasing in a food benefit program for low income people. METHODS: Participants (n=279) were randomized to groups: 1) Incentive- 30% financial incentive for fruits and vegetables purchased with food benefits; 2) Restriction- no purchase of sugar-sweetened beverages, sweet baked goods, or candies with food benefits; 3) Incentive plus Restriction; or 4) Control- no incentive or restrictions. Participants received a study-specific debit card where funds were added monthly for 12-weeks. Food purchase receipts were collected over 16 weeks. Total dollars spent on grocery purchases and by targeted food categories were computed from receipts. Group differences were examined using general linear models. RESULTS: Weekly purchases of fruit significantly increased in the Incentive plus Restriction ($4.8) compared to the Restriction ($1.7) and Control ($2.1) groups (p <.01). Sugar-sweetened beverage purchases significantly decreased in the Incentive plus Restriction (-$0.8 per week) and Restriction ($-1.4 per week) groups compared to the Control group (+$1.5; p< .0001). Sweet baked goods purchases significantly decreased in the Restriction (-$0.70 per week) compared to the Control group (+$0.82 per week; p < .01). CONCLUSIONS: Paired financial incentives and restrictions on foods and beverages purchased with food program funds may support more healthful food purchases compared to no incentives or restrictions. CLINICAL TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT02643576 .

Decision trees in epidemiological research.

BACKGROUND: In many studies, it is of interest to identify population subgroups that are relatively homogeneous with respect to an outcome. The nature of these subgroups can provide insight into effect mechanisms and suggest targets for tailored interventions. However, identifying relevant subgroups can be challenging with standard statistical methods. MAIN TEXT: We review the literature on decision trees, a family of techniques for partitioning the population, on the basis of covariates, into distinct subgroups who share similar values of an outcome variable. We compare two decision tree methods, the popular Classification and Regression tree (CART) technique and the newer Conditional Inference tree (CTree) technique, assessing their performance in a simulation study and using data from the Box Lunch Study, a randomized controlled trial of a portion size intervention. Both CART and CTree identify homogeneous population subgroups and offer improved prediction accuracy relative to regression-based approaches when subgroups are truly present in the data. An important distinction between CART and CTree is that the latter uses a formal statistical hypothesis testing framework in building decision trees, which simplifies the process of identifying and interpreting the final tree model. We also introduce a novel way to visualize the subgroups defined by decision trees. Our novel graphical visualization provides a more scientifically meaningful characterization of the subgroups identified by decision trees. CONCLUSIONS: Decision trees are a useful tool for identifying homogeneous subgroups defined by combinations of individual characteristics. While all decision tree techniques generate subgroups, we advocate the use of the newer CTree technique due to its simplicity and ease of interpretation.